Candida albicans is a pathogenic fungus that causes systemic infections and mortality in immunosuppressed individuals...Nicotinamide meets some of the key criteria required of an effective antifungal agent...For the first time in a pathogenic fungus, we combine genetics, heavy isotope labeling, and targeted quantitative metabolomics to identify genes, pathways, and mechanisms by which C. albicans can reduce the cytotoxicity of high NAM concentrations...In summary, we demonstrate that C. albicans possesses at least two mechanisms to attenuate the cytotoxicity of pharmacological NAM concentrations. It seems likely that those two mechanisms of resistance to cytotoxic NAM concentrations are conserved in many other pathogenic fungi...Although the results presented in this manuscript challenge the notion that NAM may prove valuable to treat fungal infections, there remain a number of potentially valuable strategies to augment the therapeutic efficacy of NAM.